Improve structure of the generation of documentation

	* Relocate docs dir to resources/doxygen
	* Rename NOMLIB_DOCS_DIR to PROJECT_DOXYGEN_DIR
	* Change docs output dir to within build dir (ex: nomlib/build/docs)
	* Rename html output dir to html (was public)
	* Install targets for README.md, LICENSE.md, TODO.md
Remove non-existant paths
Add include/nomlib dir to input path